# Tagged Questions

Collision detection is the determination of whether or not two or more entities make contact with each other during gameplay.

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### Collision resolution - Character walking on ascendent ground

I don't know if the solution to this problem is quite straight-foward but I really don't know how to handle collision resolution on a game where the player walks on an ascendent floor which is not ...
1k views

### 3d Collision Handling

I have trouble while detecting collisions on my 3D-Game. I have set-up Rays, to detect collisions (Screenshot) and my main-rountine already analyzes them. But now there's the question what to do ...
1k views

### map data structure in pacman

i am trying to make a pacman game in c# using GDI+, i have done some basic work and i have previously replicated games like copter-it and minesweeper. but i am confused about how do i implement the ...
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### Typical collision detection

I would like to know how is the typical collision detection of most games. For example, you control a character which can move in 2 dimensional directions (except up and down). Now lets asume he walks ...
855 views

### Collision checking problem on a Tiled map

I'm working on a pacman styled dungeon crawler, using the free oryx sprites. I've created the map using Tiled, separating the floor, walls and treasure in three different layers. After importing the ...
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### How do 2D physics engines solve the problem of resolving collisions along tiled walls/floors in non-grid-based worlds?

I've been working on implementing my SAT algorithm which has been coming along well, but I've found that I'm at a wall when it comes to its actual use. There are plenty of questions regarding this ...
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### enemy behavior with boundary to change direction

I'm doing space shooter kind of game, the logic is to reflect the enemy if it hits the boundary. With my logic, sometimes enemy behaves like flickering instead of changing the velocity. It's like ...
868 views

### XNA Per-Polygon Collision Check

I'm working on a project in XNA for WP7 with a low-poly environment, my problem is I need to setup a working per-polygon collision check between 2 or more 3d meshes. I've checked tons of tutorials ...
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### this.BoundingBox.Intersects(Wall[0].BoundingBox) not working properly

I seem to be having this problem a lot, I'm still learning XNA / C# and well, trying to make a classic paddle and ball game. The problem I run into (and after debugging have no answer) is that ...
814 views

### How does the SAT collision detection algorithm work

There are a lot of tutorials and sample code available showing how to implement the SAT collision detection algorithm. But can someone explain, without math or code, what are the general principls ...
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### How do I get the axes for SAT collision detection

In SAT collision detection how do I calculate the axes for projection?
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### Who should respond to collision: Unit or projectile?

In an RTS if a projectile hits a unit. Who should handle the collision? If projectile handles the collision, it must be aware of all possible types of units, to know what damage to inflict. For ...
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### Boat passing under a bridge in a 2D tile based RTS

I'm writing a 2D tile based RTS. And I want to add a 'pseudo 3D' feature to it - bridges over the rivers. I havent't start any coding yet, just trying to think how it fits the collision detection ...
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### 2D Collision detection for Pinball Game

So far in previous games I have used simple 2D collision with boxes then checking at pixel level for a collision. If making a pinball game in nearly a lot of frames the ball will be in contact with a ...
836 views

### Making a perfect map (not tile-based)

I would like to make a map system as in the GameMaker and the latest code is here. I've searched a lot in google and all of them resulted in tutorials about tile-maps. As tile maps do not fit for ...
5k views

### How to avoid circular dependencies between Player and World?

I'm working on a 2D game where you can move up, down, left and right. I have essentially two game logic objects: Player: Has a position relative to the world World: Draws the map and the player So ...
816 views

### Point of contact of 2 OBBs?

I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the point of ...
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### Finding the normals of an oriented bounding box?

Here is my problem. I'm working on the physics for my 2D game. All objects are oriented bounding boxes (OBB) based on the separate axis theorem. In order to do collision resolution, I need to be ...
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### Detecting pixels in a rotated Texture2D in XNA?

I know things similar to this have been posted, but I'm still trying to find a good solution... I'm drawing Texture2D objects on the ground in my game, and for Mouse-Over or targeting methods, I'm ...
2k views

### Collision Detection Game Design and Architecture

I've reading some articles about collision detection. My question here is about ideas on the design for it. Baically I have a C++ game that has a main loop with entities with an update method. Based ...
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### Normalizing the direction to check if able to move

i have a a room with 4 walls along the x and z axis respectively. My player who is in first person (therefore the camera) should have collision detection with these walls. I'm relatively new to this ...
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### What is the best way to implement collision detection using Bullet physics engine and a track generated from a curve?

I am developing a small racing gam, the track is generated from a curve. As said above, the track is generated, but not infinite. The track of one level could fit with no problem in memory and will ...
2k views

### 2D OBB collision detection, resolving collisions?

I currently use OBBs and I have a vehicle that is a rigid body and some buildings. Here is my update() private void update() { camera.setPosition((vehicle.getPosition().x * camera.getScale()) - ...
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### How to choose cell to put entity in in an uniform grid used for broad phase collision detection?

I'm trying to implement the broad phase of my collision detection algorithm. My game is an arcade game with lot of moving entities in an open space with relatively equivalent sizes. Regarding the ...
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### Moving the jBullet collision body to with the player object

I am trying to update the location of the rigid body for a player class, as my player moves around I would like the collision body to also move with the player object (currently represented as a cube)....
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### Faster 2D Collision detection

Recently I've been working on a fast-paced 2d shooter and I came across a mighty problem. Collision detection. Sure, it is working, but it is very slow. My goal is: Have lots of enemies on screen and ...
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### XNA 2D vehicle wall collisions

I am attempting to implement collisions for my truck game, where the truck can drive around the world and hit walls surrounding the level and various randomly placed walls within the level. I am able ...
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### Hit Detection When rotating the camera

This bug/feature has been plaguing me for a while and i want to know the best way to fix it. I'm testing simple hit detection with a wall, like: if (Forward button) if(Inv.w.z < -49 || ...
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### C# XNA 2D Multiple boxes collision detection and movement

Hi, I've been making simple game where you shoot boxes that are coming towards you. All game objects are simple rectangles. Now I have problem with collision detection; how to check where the ...
2k views

### How a “Collision System” should be implemented?

My game is written using a entity system approach using Artemis Framework. Right know my collision detection is called from the Movement System but i'm wondering if it's a proper way to do collision ...
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### Draw Rectangle To All Dimensions of Image

I have some rudimentary collision code: public class Collision { static boolean isColliding = false; static Rectangle player; static Rectangle female; public static void collision(){ Rectangle ...
966 views

### Platform game collisions with Block

I am trying to create a platform game and doing wrong collision detection with the blocks. Here's my code // Variables GTimer jump = new GTimer(1000); boolean onground = true; // The update method ...
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### Circle vs Edge collision detection / resolution [closed]

I made a javascript class Ball.js that handles physics interactions betweens balls as well as painting. In the v1.0, the ball vs ball collision detection and resolution is well handled. In the next ...
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### Box2d too much for Circle/Circle collision detection?

I'm using cocos2d to program a game and am using box2d for collision detection. Everything in my game is a circle and for some reason I'm having a problem with some times things are not being detected ...
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### Fixing a collision detection bug in Slick2D

My game has a bug with collision detection. If you go against the wall and tap forward/back sometimes the game thinks the speed you travelled at is 0 and the game doesn't know how to get you out of ...
493 views

### High CPU usage on Pong clone

I just made my first game, a clone of Pong, using OpenGL and C++. But its using ~50% of the CPU, which I guess is very high for a game like this. How can I improve that? Can you please look up my code ...
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### jBullet Collision/Physics not working as expected

Below is the code for one of my objects in the game I am creating (yes although this is a cube, I am not making anything remotely like MineCraft), and my issue is I while the cube will display and is ...
1k views

### Error in my Separating Axis Theorem collision code [closed]

EDIT 2: Made some more alterations, now the one area i'm still confused on is: how to work out the vector to project on the separation axes? My projectOnto(..) method has some huge gaps now and i know ...
1k views

### Collision detection on a 2D hexagonal grid

I'm making a casual grid-based 2D iPhone game using Cocos2D. The grid is a "staggered" hex-like grid consisting of uniformly sized and spaced discs. It looks something like this. I've stored the grid ...
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### How to collide with a 45degree wall in XNA

I want to make a PAC MAN imitation game to start working on AI, and while my first version will feature rectangles with widths or heights of 1 to makes walls for collision detection, I want to ...
5k views

### Why doesn't Unity's OnCollisionEnter give me surface normals, and what's the most reliable way to get them?

Unity's on collision event gives you a Collision object that gives you some information about the collision that happened (including a list of ContactPoints with hit normals). But what you don't get ...
12k views

### Collision detection, stop gravity

I just started using Gamemaker Studio and so far it seems fairly intuitive. However, I set a room to "Room is Physics World" and set gravity to 10. I then enabled physics on my player object and ...
9k views

### Fast, accurate 2d collision

I'm working on a 2d topdown shooter, and now need to go beyond my basic rectangle bounding box collision system. I have large levels with many different sprites, all of which are different shapes and ...
3k views

### Making an efficient collision detection system

I'm very new to game development (just started 3 months ago) and I'm learning through creating a game engine. It's located here. In terms of collision, I know only brute-force detection, in which case,...
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### Color based collision detection

I am making a game where you fly a ship around some randomly generated planets. Since I am using a for loop to draw over 5000 planets, using the rectangle class or an oval-type class for this is not ...
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### how to keep display tick rate steady when using continuous collision detection?

(I've just found about this forum). I hope it is ok to repost my question again here. I posted this question at stackoverflow, but it looks like I might get better help here. Here is the question: I'...
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### Unity Particle System collision detection problem

I'm using Unity 3.5.5f3 wich has the Shuriken particle system. I've made a blood particle system based on Unity's demos. (Exploding paint [Blood]) The blood is flowing and when it collides with a ...
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### How to design 2D collision callback methods?

In a 2D game where you have a lot of possible combination of collision between objects, such as: object A vs object B => object B vs A; object A vs object C => object C vs A; object A vs object D =>...